Method of coating by evaporating metals



Df 31, 1946- w. H.'coLBERT Erm. 2,413,606

METHOD 0F COATING BY EVAPORATING MTALS Filed Sept. l, 1944 A T'TOPNEYS AvPatented Dec. 31, 1946 2,413,606 METHQD OF COATIN G BY EVAPORATING lWETALS William H. Colbert and Arthur R. Weinrich,

Brackenridge, Ba., assignors to Libbey-Owens- Ford Glass Company, Toledo, Ohio, a `corporation of Ohio AApplication September l, 1944, Serial No. 552,290

14 Claims.

Our present invention relates to a novel method or process of evaporating metals, such as copper, silver, etc. It has to do more particularly with the coating or wetting by capillary attraction of a filament which, for example, may be a formed coiled wire of ordinary tungsten, tantalum, molybdenum, or columbium and the subsequent thermal evaporation from that filament onto the surface of an article of a coating of a metal or metals alloyed with small amounts of beryllium which metals in their pure, o'r com- However, with a large number of metals which it is desirable to be able to thermally evaporate mercially pure, or unalloyed state normally' neither wet theiilament nor sati-sfactorily evaporate :from the filament. Articles that may thus be provided with a reectve or metallic coating may bemade of glass, porcelain, plastic, metal, plastic Cellophane, paper, or the like, to provide, a reflective or metallized surface .coating for said article. The invention also has to do with securing wetting and with thermal evaporation of such vmetals from tungsten, tantalum,.molyb denum, or columbium laments alloyed or coated with beryllium by the application to the laments of the pure metals desired to be evaporated. 1

Methods and apparatus have previously been employed to apply coatings of metals by thermal evaporation to the faces or surfaces of such articles to produce mirrors, reectcrs or metallized materials for other purposes. In these methods it is desirable to eiiect the thermal evaporation of the metal, such as silver, copper, gold or aluminum, by applying the metal directly to an electrically energized and thus heated tungsten or other metallic filament which is preferably 1ocated within a vacuumized chamber. The. metals which may be used as filaments for such evaporations must obviously be of high melting point and also of low vapor pressure at the elevated temperatures at` which the metals applied to the filaments evaporate. Thus, tungsten, tantalum,

molybdenum and columbium have representedv the most practical materials for such use. Platinum also has been used to a small degree but its high cost is generally prohibitive. While iron and nickel are of relatively low vapor pressure, they are of such relatively low melting point that laments made from them lrapidly burn out.

With iilaments made from tungsten, tantalum, molybdenum or' columbium many of the metals can be readily evaporated. Thus,l for example, aluminum, magnesium, vanadium, barium, strontium, iron, nickel, cobalt, manganese, thorium, chromium and titanium, when applied to such laments will on heating in a vacuum, melt and spread over the lament by capillary attraction and satisfactory evaporation of these metals then occurs from the large amount of surface whichv the molten metal covers.

and which from their vapor pressure at elevated temperatures should readily evaporate, it has been found diiiicult, if not impossible, to carry out satisfactorydeposition of such coatings by thermal evaporation. Thus, for example, silver and copper while readily lending themselves to thermal evaporation from a cruci'ble, cannot be evaporated readily from a coil of tungsten, tantalum, molybdenum or columbium when applied to a filament of these metals and heated by electrical resistance. 'I'he silver or copper on melting showsino aiiinity for the metallic laments and almost immediately after melting collects into a drop and falls oil of the filament. This lack of ability to wet tungsten,l tantalum, molybdenum and columbium occurs also with the metals gold, zinc, tin, antimony, cadmium, bismuth, lead, thallium and indium. With each of these metals the use of coiled iilaments of tungsten, tantalum, molybdenum and columbium as Y.

a means of evaporating these metals has not been possible for the practical commercial production of mirrors or metallic coated articles. When vattempts are ,made to thermally'evaporate these metals from such coiled -wire iilaments, the metals after melting form into droplets and `fall oi the laments. This wastes metal and prevents any control of the thickness of the coating on lthe article.l Further,v when any metal i-s evaporated, explosive boiling or spitting ofV metal occurs causing small globs of metal to be driven forcibly onto, and in most cases into the surface of the article being coated, thus spoiling it.

Better results have been obtained in attempts to evaporate such metals by using less y*advantageous methods of holding and heating the metals such as crucibles electrically heated by variously placed Wires. But even such methods provide .no control of thickness and the coating damage done by the spitting of metal globs is still present.

We have found that we may thermally evaporate from coiled wire filaments made of tungsten, A jgantalurm molybdenum, or columbium metals that normally will not Wet nor evaporate from such filaments, by the application to such filaments or the forming thereon of alloys of these metals with small amounts of beryllium, such as 0.1% to 5% or more, which beryllium also alloys with such coiledwire filaments made of tungsten, tantalum, molybdenum or columbium in the'presence of the metals we desire to evaporate. Thus, for example we may add small amounts of beryllium to silver and when such alloys are melted on a, tungsten filament the silver will be found to wet the tungsten filament and to spread itself by capillary attraction over the surface of the tungsten wires. In the abnot seem to bring about any desirable improvement in the wetting characteristic. In each case,

however, it is found that the beryllium readily A forms alloys with tungsten, tantalum, molybdenum and columbium and also forms alloys with copper, silver, gold,` zinc, tin, antlmony, cadmium, bismuth, lead, indium and thallium.

lThus the beryllium readily brings about thel desired wetting and it appears clearly that this is accomplished through the mutual alloying tendency which these metals possess, The beryllium may also be added to the filament either as an alloy with the` tungsten, tantalum, molybdenum or columbium, or preferably it may be employed as a. surface coating or surface alloy with such filaments. Filaments containing small amounts of beryllium are found to wet readily when the pure otherwise non-wetting metals are fused thereon. Thus the wetting is brought about in the presence of the beryllium and it is immaterial as to whether the beryllium is supplied in an alloy applied to the filament or exists in the filament surface.

One of the objects ofour invention is to provide an improved and satisfactory method or process of evaporating metals which normally do not wet filament coils of tungsten, tantalum, molybdenum, or columbium, by alloying the metal to be evaporated so as to cause the metal to wet the coils of such filaments and-to coat these coils by vcapillary attraction so that thermal evaporation can then be carried out.-

Another object of our invention is to apply to a tungsten, tantalum, molybdenum or columbium filament a metal to be evaporated which does not normally wet such filament coils, alloyed with a suitable proportion of beryllium which alloys with the filament and brings about a proper wetting or coating of the filament wires by capillary attraction under the influence of heat applied to the filament.

As another object of .our invention there is provided an improved method or process whereby a metal which is to be evaporated and which does not normally wet coiled heater filaments of tungsten, tantalum, molybdenum and columbium is alloyed with beryllium and applied tosuch a filament, and by securing a wetting and coating of the filament by capillary attraction of the metal desired to be evaporated may be deposited upon the face or surface of an article, by thermal evaporation, to provide such article with a reflective or metallized surface coating.

As a further object there are provided filaments which have been pre-alloyed with small amounts of beryllium which may be used directlytofevapalloyed filaments are found to be wetted readily by the moltenpure metals desired to be evaporated. A-s a further object means are provided for forming mirror or reflective deposits of metal alloys containing -small amounts of beryllium thereby providing mirrors of somewhatdliferent reflective and color characteristics.

A further object of our invention is to apply to 'a tungsten, tantalum, molybdenum or columbiumv filament, a metalsuch as copper, silver, gold, zinc, tin, antimony, cadmium, bismuth, lead, indium or thallium, alloyed with a suitable Vproorate the normally non-wetting metals since such y portion of another metal which brings about a desirable wetting or coating ofthe filament metal by capillary attraction under the influence of heat applied to the lament and thus permits thermal evaporation of the metals.

Generally speaking, and in accordance with our present invention, the metal to be evaporated which normally does not Wet the heater filament is applied alloyed with small amounts of beryllium, such as 0.1% to 5% or more, providing wetting characteristics'to the coils of a filament which may be formed from tungsten, tantalum, molybdenum or columbium. Thus in -order to thermally evaporate copper, zinc, galiium or arsenic, which are metals of the chemical periodic table arrangement found in series 5 or the metals silver, cadmium, indium, tin and antlmony, which --include metals of series 7, or the metals gold,

thallium, lead and bismuth which in the periodic arrangement include series 11, all of which metals do not wet filaments made of tungsten, tantalum, molybdenum or columbium, we first bring about a satisfactory wetting and adhesion of these metals to the filaments by applying the metals to the filaments as an alloy' with small amounts of beryllium, and then by energizing the filament and thus heating it we cause a melting of the metals. When the applied metal alloys are thus melted they apparently alloy to some degree with the metal comprising the heater filament wire and by reason of such tendency the molten metals wet the filament wires and by capillary attraction are drawn out over the surface of the coils. The molten metal which has thus covered considerable surface of the heated coil and is held thereto by capillary attraction is thereafter evaporated uniformly from the heater coils to apply a surface coating of a metallic or refiective nature to an article such as a piece of glass, porcelain, silica, mica, plastic, metal, Cellophane, resin, or other support material, by deposition resulting from the thermal evaporation of the metal from the filament. The operations of thermal evaporation may with some of the metals, -be carried out at normal pressure but generally are preferably carried out in vacuum chambers known to the art and within a high vacuum, which may be of the-order of one millimeter down to 10 to the minus 5 millimeters or better. It is very necessary that the metal to be evaporated wet and coat the coil surfaces in order that the metal will evaporate uniformly in all directions. By securing such wetting action the thermal deposition of these metals, in addition to being made possible, has been found by our process to give uniform coatings.

We may also proceed to secure the objects within the scope of this invention by supplying beryllium in the filament either as an alloy with the tungsten, tantalum, molybdenum or columbium, or as a surface coating; or as 'a surface alloy on such filaments. When the pure metals such as silver, copper or gold which will not normally wet the pure tungsten, tantalum, molybdenum or columbium filaments are applied to these filaments containing some beryllium they will on melting. readily wet the beryllium-containing filaments. Thus, in general, the invention comprises melting the metal desired to be evaporated upon a tungsten, tantalum, molybdenum or columbium filament in the presence of beryllium which brings about the desired wetting and adherence of the molten metal to the heated filaments.

As will be shown more fully later, pieces of the metal to be evaporated and which have been pre. viously alloyed with the metal which brings about the alloying with and wetting of the filament, may be hung onto the loops or coils of the filament.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claims when consideredrin connection with the accompanying drawing forming a part of this specification wherein similar reference characters designate corresponding parts in the several views.

In said drawing:

Figure 1 is a perspective view, partly broken away, illustrating one suitable apparatus for carrying out our improved method or process.

Figure 2 is a perspective view of a fragment of an electric filament showing the application of a suitable metal alloy to several of the coils or convolutions thereofyand illustrating onephase of the method or process of wetting or coating the filament by said alloy; and

Figure 3 is a View similar to Figure 2 showing the filament after the vcompletion of the wetting process by the alloy of Figure 2.

Figure 4 is an enlarged, cross-sectional view of a tungsten, tantalum, molybdenum or columbium electric resistance filament precoated with a thin layer of beryllium.

Figure 5 is another enlarged, cross-sectional View showing a filament of tungsten, tantalum,

molybdenum or columbium which is alloyed only in the surface of the filament with beryllium.

Figure 6 is also an enlarged, cross-sectional view of a filament formed from tungsten, tantalum, molybdenum or columbium, which is alloyed throughout with a small amount of beryllium and upon which the pure metals, on melting, will directly show a good wetting action,

Figure 7 is a perspective view of a filament containing berlyllium such as Shown in Figures 4, 5 and 6 and upon which pieces of the pure metal to be evaporated have been hung.

Figure 8 is a perspective view after the filament and pieces of metal of Figure 7 have been heated to effect a wetting of the filament.

Before explaining in detail `the present invention it is to be understood that the invention ris not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of -being practiced or carried out in various ways. It is to be understood also that the phraseology or terminology employed' herein is for the purpose of description and not of limitation, and it is not intended to limit the invention herein claimed beyond the requirements o'f the prior art.

Referring now to the drawing, we have shown a suitable apparatus for carrying out our improved method or process, as well as one suitable metal alloy and the steps of applying the alloy or a filament by a wetting action resulting from capillary attraction. We have also shown -suitable alloyed filaments and the steps of applying the pure meta] to be evaporated to such filaments and the wetting action upon the filament resulting from capillary attraction after the pure metal is melted.

Suitable apparatus employed by us, and illustrated in Figure 1, comprises, as shown, a supporting base I Il upon which is mounted a housing, shown as a whole at II. The housing II may be in the form of a bell-jar or' the like having a dome-like or senil-spherical top portion or enporting posts I5 between which is carried or supev ported, in substantially horizontal position, an electric filamen-t I6. The filament, as shown, is in the form of a coiled wire made of tungsten, tantalum, molybdenum or columbium, or an alloy of these with beryllium or precoated with a layer of beryllium, whose opposite ends are attached to brackets I1 mounted upon the supporting posts I5 and adjustable thereon so as to vary the posi.- tion or location of the filament I6 with relation to the supporting base I0.

'I'he chamber provided by the housing Il may,

if desired, be completely evacuated of air through outlet pipe or conduit I0a and have a high vacnum-created therein by means of suitable air evacuating and vacuum creating means, such as a pump (not shown).

In accordance with one method embodying our invention which is to be performed or carried out within the chambered housing I I, we preferably provide a metal alloy which may consist of silver, copper or gold or other normally non-wetting metal and approximately 0.1% to 5% or more of Iberyllium. Pieces of this preformed silver and beryllium alloy, or copper and beryllium alloy, or gold and beryllium alloy, several of which are shown at I8, in Figures 1 and 2, are bent and hung on the loops or convolutions IBa of the fllament I6 composed of ordinary commercially pure tungsten, tantalum, molybdenum or columbium in the manner shown.

It is known lthat silver, copper and gold lend .themselves admirably to thermal evaporation but they have no wetting aiiinity for tungsten, tantalum, molybdenum or columbium surfaces and therefore silver, copper or gold alone is unsatisfactory for coating the filament I6 formed from either of these metals by a wetting action effected by capillary attraction. Wetting of the filament wire is essential to secure a maximum of evaporating surfaces to provide evaporation uniformly in all directions, to the securingof uniform deposits, and also to avoid the dropping of the molten metal off the heater wires. We have found that beryllium readily alloys with silver, gold and copper and the alloys have a wetting aflinity for the four above-mentioned metals, any one of which may be used for making the filament I6, and thus beryllium lends itself particularly well to securing the wetting of the filament by capillary attraction. Therefore, by including a certain percentage of beryllium, preferably 0.1% to 5% or more, with the silver, copper or gold to form the alloy I8, the beryllium will serve to bring about wetting or coating of said filament by the molten metal by capillary attraction when the filament is energized and thus heated and will act .to cause the silver, copper or gold to also cling to or wet the filament. An early stage or phase of the wetting action of the filament I 6' by the alloy I8 is shown generally at I9, Figure 2. As .the wetting action by capillary attraction continues, the two metals of the alloy will proceed .to wet the coils of the filament I6 and in fact,

will substantially wet or coat and cover the surfaces of the filament. In Figure 3, we have illustrated several of the coils or loops I6a of the filament as being coatedat 20 by the alloy from which the pieces I8 are formed.

Thus, by including beryllium with the silver, copper or gold, as an alloy, it is possible to quickly and effectively coat or wet the filament I6 by capillary attraction. Since, therefore, the alloy builds up onto the surfaces of the filament in substantially the Vmanner illustrated in Figure 3, there will be a relatively uniform coatingor wetting of the filament and a uniform dependable evaporation of the silver, copper or gold. Heretofore, when attempts were made to wet the filament by the use of the silver, the copper or the gold alone, only small portions of the molten metal would cling to the filament as droplets hanging from the lower ends of the coils of the Cil ` the bell jar II is lowered, the vacuum is created,

filament, with the major portion of the molten metal dropping or falling off the coils. This was particularly undesirable since it'was practically impossible to produce, by thermal evaporation, an even surface coating by deposition, or to control the deposition to desired coating deposit thicknesses on the surface of an article, such as the article I4, to which it was desired to apply a reilective surface coating. By virtue lof the fact that the silver, copper or gold did not properly wet the tungsten or other metal filament but had a tendency to drop oli said filament, the process of coating with these metals by deposition was unsatisfactory, slow and painstaking because only a small portion or percentage of the filament received the metal coating. Considerable shutting down and starting over again was required when most of the gold, silver or copper on first melting dropped olf the coils and no evaporation was secured. Thus great waste occurred, the process was considerably slowed down, and the coating produced by deposition, if any, was uneven or spotty and unsatisfactory because of such uneven character thereof on the surface of the article coated. Commercial production under such uncertain conditions was impossible.

It'is to be understood that in carrying out our method or process as described above, in the chamber of the housing I I, the chamber depending upon the metal being evaporated, may be at atmospheric pressure, or it may be evacuated of air and a vacuum created therein. Thus, after the Pieces I8 of the silver' and beryllium alloy or copper and beryllium alloy or gold and beryllium alloy, as the case maybe, have been applied to the coils of the filament I6 and the work piece I4 mounted upon its support I3 within the chamber, a vacuum of 10 to the minus 3 millimeters or better is created and the lament I6 is then energized and therefore heated so as` to melt the alloys and to start in motion the wetting action of the filament by capillary attraction, as explained above. After the wetting action has been completed as illustrated generally at 2li in Figure 3, the filament I6 is furtherenergized to increase the heat therein, whereby silver, copper, or gold in the coating 2li-of the alloy will be thermally evaporated and transferred by deposition to the faceor surface of the work piece I4 which, as shown, is disposed in a position opposite the filament I6.

We have found that the desired wetting may also be brought about by applying pure metals as pieces, as shown at 23 in Figure 7, to a filament of tungsten, tantalum, molybdenum or columbium, indicated at I6 which has been precoated and electric current is applied to the filament through the electrodes I5 to cause melting of the applied pieces and a wetting of the coil as illustrated in Figure 8. By continued application of heat to the coil the applied metal will be thermally evaporated ,and deposited upon the object I4.

During the evaporation of the higher boiling metals such as gold, silver and copper, considerable of the beryllium is also distilled while in the case of the lower boiling metals such as lead and zinc, where the filaments are operated at relatively low temperatures, little of the berylliumwhether present originally as an alloy with the metal to be distilled or present in or on the filament is distilled. Thus, in the latter case practically pure lead or zinc coatings are deposited whereas in the case of gold, silver or copper an alloy of beryllium and these metals is thermally deposited upon the object being coated. In the case of copper and gold this alloying has been found to `lead to desirable results in varying the shade or color of the produced mirrors. when evaporating alloys of beryllium and copper the shade while still primarily red becomes progressively lighter and yellower in contrast to the bright red reflection tones of a pure copper mirror. A copper-beryllium alloy containing 2% of beryllium wets pure heater fllamaents of tungsten, tantalum, molybdenum or columbium completely and the mirror produced by the thermal evaporation of this alloy is of a light, red, yellow shade complished by the decrease of surface tension 'forces accompanying the wetting and also in the elimination of conditions leading to super-heating by getting the metal to spread out in a thin coating over most of the filament surfaces.

The precoating of filaments with beryllium as shown in Figure 4 may be accomplished by electroplating or by hot-dipping in molten beryllium so as to place thereupon a thin coating of beryl- .lium such as .0002 to .0003 inch thick upon a filament approximately 0.035 inch in diameter. Such filaments may be heated to cause the beryllium to surface-alloy with the filament to produce structures as illustrated by Fig. 5. Where it is desired to introduce beryllium into the filament as a uniform alloy this may be accomplished by introducing approximately 1 to 3% or more of beryllium into a molten alloy and thereafter in the known manner producing wire by pulling such alloy through dies. Y

From the foregoing it will be seen that we have providedan improved method or process for applying certain metals to a filament of tungsten, tantalum, molybdenum or columbium by causing a wetting resulting from capillary attraction through the presence of small quantities of beryllium and applying Vheat from the filament, and

Thus

have thereby been able to carry out evaporation of such metalsafter the wetting action has been completed by thermally evaporating the metals and have caused their deposition upon the face or surface of a work piece to provide metallized lr reflective surface therefor. It will also be seen that while we secure the desirable requisite of wetting of the laments of tungsten, tantalum, molybdenum or columbium, by metals which normally do not wet these, by the presence of beryllium this may be accomplished in several ways. Thus, we may apply separate pieces of a preformed alloy of such metals with beryllium and these will wet the pure metallic filaments, or we may apply the pure metals to be evaporated to a lament containing some beryllium, either in its surface or throughout.

While we have referred to the use of tungsten, tantalum, molybdenum, or columbium as suitable metals from which 4the coiled filament or element I6 may be formed, other suitable metals may be used for this purpose. We have mentioned these metals particularly since their high melting points and low vapor pressures at the boiling temperatures of other metals make these the practically desirable metals for use as such filaments.

We have described our improved method or process as preferably being carried out in av vacuumized chamber'in which the step of wetting the filament takes place,` as does also the step of thermal evaporation of the metal to effect its deposition upon the workpiece toprov'ide a re iective coating thereupon.

Obviously also in` the case of the most readily volatilev metals, such as cadmium and zinc, the melting ofthe metals and the wetting of the filaments, as well as the evaporation of the readily volatile metals, such as cadmium or zinc, may be carried out under atmospheric conditions of pressure if desired, while employing a suitable inert atmosphere.

Having thus described our invention, what we claim is:

1. The method of making mirrors by the deposition of a metal on a polished support material, comprising evaporating a metal from a filament made of a metal selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the metal to be evaporated is heated on such filament as an alloy with beryllium which causes the metal desired to be evaporated to wet, to adhere to, and to spread out over the filament surfaces and by the continued application of heat, to evaporate, and depositing a' coating thereof on said polished support material.

2. The method ofcoating surfacesv which comprises evaporating metals from a filament made of a metal selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the metal to be evaporated is heated on such filament as an alloy with, beryllium which causes the metal desired to be evaporatedto wet, to adhere to, and to spread out over the lament surfaces and by the continued application 0! heat.

to evaporate and to deposit upon said surfaces.`

3. The method of coating articles by evaporatto be evaporated to wet, to adhere to, and to spread out over the filament surfaces and by the continued application of heat, to evaporate and to coat the articles by deposition of the silver thereon.

4. The method of coating a support material by evaporating silver within a vacuum from a filament selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the silver is heated on such filament in the presence of beryllium to form an alloy and wherein said beryllium alloyed with the silver causes the silver desired to be evaporated to wet, to adhere to, and to spread out over the filament surfaces and by the continued application of heat, to evaporate within the vacuum and to coat by deposition said support material.

5. The method of coating a support by evaporating copper from a filament selected from the group consisting of tungsten, tantalum, molybdenum and columbium whereinv the copper is heated on such filament in the presence of beryllium to form an alloy and wherein said beryllium alloyed with the copper causes the copper ing silver from a filament selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the silver` is alloyed with beryllium and is heated on such lament and wherein said beryllium causes the silver desired desired to be evaporated to wet, to adhere to, and to spread out over the filament surfaces and by the continued application of heat, to evaporate and to coat by deposition thereof on a surface of the support.

6. The method of coating a support by evaporating copper within a vacuum from a lament selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the copper is alloyed with a relatively small amount of beryllium and is heated on such lilament and wherein said beryllium causes the copper desired to be evaporated to wet, to adhere to, and to spread out over the iilament surfaces and by the continued application of heat, to evaporate within the vacuum, and to coat the support by deposition. g

'7. The method according to claim 4 wherein gold is substituted for silver.

8. A method according to claim 1, wherein the beryllium is present in a relatively small amount.

9. A method according to claim 2, wherein the beryllium is present in an amount less than 5%.

10. A method according to claim 3, wherein the beryllium is present in an amount under 5%.

11. A method according to claim 4, wherein the beryllium is present in a relatively small amount.

12. A method according to claim 4, wherein gold is substituted for silver and wherein the beryllium is present in an amount less than 5%.

13. The method of coating a support material.

by evaporating a metal within a vacuum from a filament selected from the group consisting of tungsten, tantalum, molybdenum and columbium wherein the metal is heated on said filament in the presence of beryllium to form an alloy and wherein said beryllium alloyed with the metal causes the metal desired to be evaporated to wet, to adhere to, and to spread out over the filament surfaces and by the continued application of heat, to evaporate within thevacuum and to coat by deposition said support material.

14. A method according to claim 13, wherein the support material is a polished support material.

WILLIAM H. COLBERT. v ARTHUR R. WEINRICH. 

